Bedrust

BackgroundDifferent variables in the IUI procedure have been well investigated: semen preparation techniques (gradient, swim-up or wash and centrifugation), IUI in natural versus stimulated cycles and single versus double insemination. One of the issues that remains unresolved is the question whether after insemination the patient can immediately mobilize or should stay in supine position for a short period of time.Several studies have investigated sperm migration and survival in thefemale genital tract. Spermatozoa may reach the fallopian tube - the site of fertilization - within 2 to 10 minutes. In IUI the sperm is deposited directly inside the uterine cavity, and therefore close to the site of fertilisation. This suggests that sperm migration to the site of fertilization is independent of the position of the female directly after IUI. In 2000 however, Saleh et al reported a significantly increased cumulative pregnancy rate per IUI-cycle and per couple in favour of women staying in supine position for 10 minutes after IUI as compared to immediate mobilization. Unfortunately, this randomized controlled trial was underpowered and unbalanced. Therefore the effect of "bed rest" after IUI remains unclear.

ObjectiveOur objective is to answer the question whether a short time of immobilization (i.e. 15 minutes) has a potential advantage on pregnancy rates after intra-uterine insemination, overimmediate mobilization and outweighs the disadvantage of the extra timeand working space it consumes.

Study designIt is a multi centre randomised controlled trial.

PopulationAll patients, above 18 years of age, receiving IUI with fresh orcryo-preserved donor- or husband's sperm and IUI with or without controlled ovarian hyper stimulation (IUI-COH), as a treatment for their subfertility will be eligible for the trial.

Intervention and follow-upIntra uterine insemination will beperformed in spontaneous cycles as well in cycles with controlled ovarian hyperstimulation (COH). Insemination will be performed in lithotomy position with Trendelenburg tilt. After the insemination has been performed, the patient will, according to their allocation, immediately stand up and go home, or will return to normal supineposition, and remain so for 15 minutes. Follow up of each included patient will be until 3 cycles of IUI, or in case of pregnancy, until12 weeks of gestation.

Outcome measures and analysisThe analysis will be performed according the intention to treat principle. The primary outcome measure is ongoing pregnancy per couple. Primary and secondary outcome measures will be expressed in pregnancy rates per couple and relative risks with 95% confidence intervals. With use of life-table analysis (Kaplan-Meiercurves) the cumulative probability of pregnancy will be estimated in the two groups. The treatment effect will be expressed as a hazard rateratio. Measures for uncertainty will be expressed using 95% confidence intervals. Using an alpha-error of 0.05 and a beta-error of 0.20, and assuming a drop-out rate of 10%, 185 couples are needed in each arm tojudge whether bed rest is superior over immediate mobilisation.